Omnidirectional pinion wheel

ABSTRACT

Concepts of an omnidirectional pinion wheel are described. In one embodiment, the wheel includes a hub, first and second annular rims each including inner and outer rim surfaces, spokes that extend from the hub to the first and second annular rims, a pinion ring including pinion rods that extend between the inner surfaces of the first and second annular rims, and first and second annular rings of rollers affixed on the outer surfaces of the first and second annular rims. Using an axis of freedom of the rollers, the wheel can move sideways in addition to forward and backward. Further, when used with a vertical rack gear, the wheel can provide vertical displacement by engagement between teeth of the gear and the pinion ring. Additionally, various racks and tracks with teeth for pinion ring engagement are described along with an example vehicle capable of vertical displacement using the wheels.

BACKGROUND

Robotic systems can be useful in warehouse and fulfillment centeroperations. Among other tasks, robotic systems can be relied upon forpicking, placing, and moving items. As another example, items can bemoved from place to place in a warehouse using robotic systems toautomate package handling operations. These robotic systems often relyupon one or more wheels. As one of the simple machines, a wheel is acircular component that can be rotated to facilitate movement ordisplacement. In connection with an axle, a wheel can be used to moveobjects by supporting a load while also permitting rotation that leadsto displacement.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure can be better understood withreference to the following drawings. It is noted that the elements inthe drawings are not necessarily to scale, with emphasis instead beingplaced upon clearly illustrating the principles of the embodiments. Inthe drawings, like reference numerals designate like or corresponding,but not necessarily the same, elements throughout the several views.

FIG. 1 illustrates a perspective view of an example omnidirectionalpinion wheel according to various embodiments.

FIG. 2 illustrates a side view of the omnidirectional pinion wheel shownin FIG. 1 according to various embodiments.

FIG. 3 illustrates a cross-sectional perspective view of theomnidirectional pinion wheel shown in FIG. 1 engaged with a rackaccording to various embodiments.

FIG. 4 illustrates a perspective view of another example omnidirectionalpinion wheel according to various embodiments.

FIG. 5A illustrates a perspective view of another exampleomnidirectional pinion wheel according to various embodiments.

FIG. 5B illustrates a cross-sectional perspective view of the exampleomnidirectional pinion wheel shown in FIG. 5A according to variousembodiments.

FIG. 6 illustrates a side view of another example omnidirectional pinionwheel according to various embodiments.

FIG. 7A illustrates an example vehicle including omnidirectional pinionwheels according to various embodiments.

FIG. 7B illustrates a plan view of a bottom of the vehicle shown in FIG.7A according to various embodiments.

FIGS. 8A-8C illustrate plan views of other arrangements of wheelsaccording to various embodiments.

FIG. 9A illustrates another example vehicle including omnidirectionalwheels according to various embodiments.

FIG. 9B illustrates a vehicle and a pallet tender transferring items offa rack and onto the vehicle according to various embodiments.

FIG. 10A illustrates a perspective view of an example track for verticaldisplacement of omnidirectional pinion wheels according to variousembodiments.

FIG. 10B illustrates a cross-sectional view of the track shown in FIG.10A according to various embodiments.

FIG. 10C illustrates a cross-sectional view of the track shown in FIG.10A with the omnidirectional pinion wheel shown in FIG. 1 inside thetrack according to various embodiments.

FIG. 11A illustrates a cross-sectional view of another example trackaccording to various embodiments.

FIG. 11B illustrates a cross-sectional view of another example trackaccording to various embodiments.

FIG. 12A illustrates a perspective view of an example track for verticaldisplacement of omnidirectional wheels according to various embodiments.

FIG. 12B illustrates a cross-sectional view of the track shown in FIG.12A with an omnidirectional wheel shown inside the track according tovarious embodiments.

FIG. 13A illustrates a plan view of an example system foromnidirectional transport according to various embodiments.

FIG. 13B illustrates a side view of part of the example system shown inFIG. 13A according to various embodiments.

FIG. 14 illustrates an example process of omnidirectional vehicletransport performed using the system 1300 shown in FIGS. 13A and 13Baccording to an example embodiment described herein.

DETAILED DESCRIPTION

As noted above, a wheel is a circular component that can be rotated tofacilitate movement or displacement. In connection with an axle, a wheelcan be used to move objects by supporting a load while also permittingrotation that leads to displacement. However, a conventional wheeloffers displacement only in the direction perpendicular to its axle.Thus, especially in tight or enclosed spaces, vehicles that incorporatewheels may be limited in their ability to change their direction ofmotion. For example, a vehicle may be able to travel forward andbackward using its wheels, but the vehicle may not be able to stop andimmediately move to the right or left without turning. Further,conventional wheels are not generally relied upon to provide verticalmovement or displacement.

To address certain limitations of conventional wheels, embodiments ofomnidirectional wheels, vehicles that include omnidirectional wheels,and systems and methods for omnidirectional transport are describedherein. Various omnidirectional or mecanum wheels including structuralfeatures, such as pinion rings, for example, formed to engage with racksor tracks are described. The racks or tracks include teeth formed toengage with the structural features of the omnidirectional wheels asthey rotate or drive along the tracks. Due to their design, theomnidirectional wheels are capable of holonomic or longitudinal andlateral movement on any given surface level. Further, when engaged witha rack or track that extends vertically, the wheels are also capable ofvertical movement, because they remain engaged with the rack or track asit extends vertically. As such, the omnidirectional wheels can bemaneuvered or driven in three orthogonal directions, includinglongitudinal, lateral, and vertical directions.

Example vehicles that incorporate the omnidirectional wheels describedherein are likewise capable of longitudinal and lateral movement on anygiven surface level. Further, when the vehicles are positioned to engagewith one or more racks or tracks that extend vertically, the vehicle isalso capable of vertical movement, because it remains engaged with therack or track as it extends vertically. Thus, the vehicle can bemaneuvered in longitudinal and lateral directions on a first surface,driven in engagement with a rack or track to raise or lower the vehicleto a second surface, and then maneuvered in longitudinal and lateraldirections on the second surface. Based on the ability to move invarious directions among levels of dense storage racks in a materialshandling facility, for example, the vehicle can be relied upon to pickand place items among the levels.

Example systems that incorporate vehicles having omnidirectional wheelsand racks or tracks including teeth formed to engage with the wheels arealso described. The racks or tracks can be positioned in any desiredarrangement among multiple levels of storage racks in a materialshandling facility, for example, to allow engagement of the vehicles withthe tracks for three-dimensional movement, picking items on variouslevels, placing items on various levels, and other automated tasks.

Turning to the drawings, FIG. 1 illustrates a perspective view of anexample omnidirectional pinion wheel 100 according to variousembodiments, and FIG. 2 illustrates a side view of the omnidirectionalpinion wheel 100 shown in FIG. 1. According to aspects of theembodiments described herein, the omnidirectional pinion wheel 100 canbe used in a vehicle to achieve movement in three dimensions, such as inat least three orthogonal directions, as described in further detailbelow.

Before continuing, it is noted that the wheel 100 is not necessarilydrawn to scale in FIG. 1. The wheel 100 can be any suitable sizedepending upon various factors, such as load-bearing capacity, spaceconstraints, vehicle size, etc. Further, the relative sizing of theindividual parts of the wheel 100 in FIGS. 1 and 2 is not intended to belimiting of the scope of the embodiments. In other words, in otherembodiments, one or more of the parts of the wheel 100 can be larger orsmaller as compared to that shown. Overall, rather than limiting thescope of the concepts described herein, the wheel 100 in FIGS. 1 and 2is illustrated to convey the principles of omnidirectional wheels thatincorporate a pinion, sprocket, or other related structure to facilitatevertical displacement. Finally, for clarity in illustration, where thewheel 100 (and other wheels described herein) includes several of thesame or similar parts, only a subset of those parts is individuallyreferenced in FIGS. 1 and 2, although the structure, function, andpurpose of the remaining unreferenced parts can be understood byassociation.

Referring to FIGS. 1 and 2, the omnidirectional pinion wheel 100includes a hub 110 having an axis of symmetry A and a center bore 112.The wheel 100 further includes a first annular rim 120, a second annularrim 130, a first wheel body that extends radially away from the hub 110to the first annular rim 120, and a second wheel body that extendsradially away from the hub 110 to the second annular rim 130. In theembodiment illustrated in FIGS. 1 and 2, the first wheel body includesspokes 140, and the second wheel body includes spokes 142. In otherembodiments, the body of the wheel 100 can be formed from spokes thatdiffer in shape, size, position, and/or number from that illustrated inFIGS. 1 and 2. Additionally or alternatively, the body of the wheel 100can be formed as a solid or perforated disk of material or as any othersupporting wheel body structure in any suitable thickness.

Referring to FIG. 2, the first annular rim 120 includes a first riminner surface 122 and a first rim outer surface 124, and the secondannular rim 130 includes a second rim inner surface 132 and a second rimouter surface 134. The first rim inner surface 122 is spaced apart fromthe second rim inner surface 132 by a distance X in the direction of theaxis of symmetry A of the hub 110. As shown in FIGS. 1 and 2, the wheel100 further includes a pinion ring. The pinion ring includes pinion rods150 that extend in the direction of the axis of symmetry A between thefirst rim inner surface 122 and the second rim inner surface 132. InFIG. 2, the pinion rods 150 are spaced substantially evenly along thefirst annular rim 120 and the second annular rim 130, although otherspacings can be used. As described in further detail below, the pinionrods 150 of the pinion ring can engage into the teeth of a rack toachieve vertical displacement using the wheel 100.

To achieve movement or displacement in the direction of the axis ofsymmetry A of the hub 110, the wheel 100 includes first and secondannular rings of rollers. The first annular ring of rollers includes thefirst rollers 160 arranged in a first ring and affixed to the first rimouter surface 124 of the first annular rim 120, and the second annularring of rollers includes the second rollers 170 arranged in a secondring and affixed to the second rim outer surface 134 of the secondannular rim 130. The first rollers 160 are affixed to the first rimouter surface 124 through axles that provide a rotational axis offreedom about an axis of symmetry. Similarly, the second rollers 170 areaffixed to the second rim outer surface 134 through axles that provide arotational axis of freedom about an axis of symmetry. The axles for thefirst rollers 160 and the second rollers 170 are secured or held inplace by the first roller ring abutments 162 and the second roller ringabutments 172, respectively. The first roller ring abutments 162 aresecured to or integrally formed with the first rim outer surface 124,and second roller ring abutments 172 are secured to or integrally formedwith the second rim outer surface 134. As shown in FIG. 2, the firstrollers 160 and the second rollers 170 extend a greater distanceradially away from the hub 110 than the first annular rim 120 and thesecond annular rim 130.

In FIG. 2, an axle 164 of one of the rollers 160 is shown by hiddenlines. The axle 164 provides a rotational axis of freedom about the axisof symmetry B. In the embodiment of the wheel 100 shown in FIGS. 1 and2, the axis of symmetry B is substantially orthogonal to the axis ofsymmetry A of the hub 110. That is, the angle φ between the axis ofsymmetry B and the axis of symmetry A is about 90°.

The first annular ring of the first rollers 160 is symmetrically offsetfrom the second annular ring of the second rollers 170. That is, asshown in FIGS. 1 and 2, the first rollers 160 are aligned in part acrossthe wheel 100 with the second roller ring abutments 172, and the secondrollers 170 are aligned in part across the wheel 100 with the firstroller ring abutments 162. Due in part to this offset alignment of thefirst rollers 160 and the second rollers 170, the wheel 100 can standupright on the surface 200 in FIG. 2 with one of the first rollers 160and one of the second rollers 170 resting on the surface 200, with oneof the first rollers 160 and two of the second rollers 170 resting onthe surface 200, or with two of the first rollers 160 and one of thesecond rollers 170 resting on the surface 200.

Further, using the rotational axis of freedom of the first rollers 160and the second rollers 170, the wheel 100 can be displaced on thesurface 200 in the direction of the axis of symmetry A of the hub 110(i.e., sideways to the right or left of the page in FIG. 2) in responseto a force on the wheel 100 which is, at least in part, in the directionof the axis of symmetry A. Further, in response to rotation of the wheel100 about the axis of symmetry A, the wheel can be displaced on thesurface 200 in a direction substantially orthogonal to the direction ofthe axis of symmetry A (i.e., forward into or backward out of the pagein FIG. 2). As described in further detail below, the wheel 100 can berotated by a motor or other engine through an axle secured in the centerbore 112 of the hub 110. Also, the first rollers 160 and the secondrollers 170 can be either free to rotate without being independentlydriven or can be directly driven by motors in the wheel 100, such as bymicro-motors embedded in the first roller ring abutments 162 and thesecond roller ring abutments 172.

The wheel 100 can be formed from any suitable material or materialsdepending upon its application of use and/or other factors. For example,the body of the wheel 100 can be formed from metal, plastic, or anyother suitable material or combination of materials, without limitation.Similarly, the first rollers 160, the second rollers 170, the pinionrods 150, and the other parts of the wheel 100 can be formed from metal,plastic, or any other suitable material or combination of materials,without limitation. The type of material or materials from which thewheel 100 is formed can be selected based on the application for whichthe wheel 100 is designed. For example, if the wheel 100 is designed fortransportation of relatively large and/or heavy items, then the wheel100 can be constructed from a material of relatively high strength, evenif the material is heavy. On the other hand, if the wheel 100 isdesigned for transportation of relatively small and/or light items, thenthe wheel 100 can be constructed from a material of suitable strengthbut relatively lighter weight.

Among embodiments, the wheel 100 can be manufactured and assembled inany suitable manner for sufficient strength and durability for theapplication. For example, the body of the wheel 100 and the pinion rods150 can be formed integrally together, or holes or other openings can bedrilled or otherwise formed in the first rim inner surface 122 and thesecond rim inner surface 132 for insertion of the pinion rods 150.Likewise, the body of the wheel 100, the first roller ring abutments162, and the second roller ring abutments 172 can be formed integrallytogether, or the first roller ring abutments 162 and the second rollerring abutments 172 can be secured to the first rim outer surface 124 andthe second rim outer surface 134. It is noted that the wheel 100 caninclude other parts, such as bearings, screws, bolts, or otherfasteners. It is also noted that an axle can be secured to the wheel 100using fasteners, mating cross-sectional profiles of the center bore 112and the axle, friction, or other ways.

To illustrate how the wheel 100 can be used to achieve verticaldisplacement, FIG. 3 illustrates a cross-sectional perspective view ofthe wheel 100 engaged with a rack 300. It is noted that, because spacein materials handling and other facilities is often limited, manyfacilities make use of multiple floors, layers, levels, or platforms inrack or shelving structures. Without the use of ramps, elevators, etc.,it may not be possible for vehicles in such a facility to reach ortraverse across multiple floors or levels. In that context, using thewheel 100, a vehicle can engage a rack, such as the rack 300, to climbup the side or edge of shelving or other support structures to reachvarious levels in a facility. An example of such a vehicle is describedin further detail below with reference to FIGS. 7A and 7B.

Referring to FIG. 3, the second annular rim 130, second rollers 170, andsecond roller ring abutments 172 are omitted from view, so that theengagement of the pinion rods 150 with the rack 300 can be more clearlyseen. As shown, the pinion rods 150 engage with the teeth 310 of therack 300. More particularly, as the wheel 100 is rotated clockwise aboutthe axis of symmetry A, the wheel 100 is displaced vertically in thedirection C because the pinion rods 150 progressively engage higherteeth 310 along the rack 300. Similarly, as the wheel 100 is rotatedcounter-clockwise about the axis of symmetry A, the wheel 100 isdisplaced vertically in the direction D because the pinion rods 150progressively engage lower teeth 310 along the rack 300. As describedbelow, in certain embodiments, teeth similar to the teeth 310 of therack 300 can be formed inside a partially-enclosed track or rail, andthe wheel 100 can be driven into the track or rail for verticaldisplacement between different platforms in a materials handlingfacility, for example. An example of such a system is described infurther detail below with reference to FIGS. 10A-10C, 11A, 11B, 12A, and12B.

Before turning to the other example wheel embodiments in FIGS. 4, 5A,5B, and 6, it is noted that the sizing, number, and relative positionsof the pinion rods 150 of the wheel 100 can vary from that shown inFIGS. 1-3. For example, the pinion rods 150 can extend a distance thatis greater or smaller than the distance X shown in FIG. 2. Also, thewheel 100 can include a greater or lesser number of pinion rods 150, andthe pinion rods 150 can be more closely spaced together or furtherspaced apart. Also, the pinion rods 150 can be placed closer to orfurther apart from the first annular rim 120 and the second annular rim130. The sizing, number, and relative positions of the pinion rods 150can be chosen based in part on the amount of weight to be carried andlifted by the wheel 100 and/or other factors. Similarly, the sizing,number, and relative positions of the teeth 310 of the rack 300 can bechosen based in part on the amount of weight to be carried and/or liftedby the wheel 100. Finally, it is noted that, although the pinion rods150 are illustrated in FIGS. 1-3 as having circular cross sections, thepinion rods 150 can be formed having any suitable cross-sectional shape,such as triangular, square, trapezoidal, or other shapes.

FIG. 4 illustrates a perspective view of another example omnidirectionalpinion wheel 400 according to various embodiments. Among other elementssimilar to the wheel 100, the wheel 400 includes a hub (not shown inview), an annular rim 420, and a wheel body (not shown in view) thatextends radially away from the hub to the annular rim 420. The annularrim 420 includes a first rim surface 422 and a second rim surface 424.

The wheel 400 further includes first and second annular rings ofrollers. The first annular ring of rollers includes the first rollers460 arranged in a first ring and affixed to the first rim surface 422 ofthe annular rim 420, and the second annular ring of rollers includes thesecond rollers 470 arranged in a second ring and affixed to the secondrim surface 424 of the annular rim 420. As shown in FIG. 4, the firstrollers 460 and the second rollers 470 extend a greater distanceradially away from the hub than the annular rim 420.

The wheel 400 further includes a pinion ring. The pinion ring includespinion rods 450 that extend out a distance Xb in a direction of an axisof symmetry of the hub of the wheel 400 from the wheel body of the wheel400 to the ring rim 452. The pinion rods 450 are spaced substantiallyevenly in a ring similar to the pinion ring of the wheel 100 in FIGS. 1and 2, but extending from one side of the wheel 400 rather than in thecenter between the two annular rings of rollers. Similar to the pinionrods 150, the pinion rods 450 can engage into the teeth of a rack toachieve vertical displacement when the wheel 400 is rotated. The pinionrods 450 are shown in FIG. 4 to extend a distance Xb that is differentthan the distance X in FIG. 2, to provide an example of variations amongthe embodiments, but the pinion rods 450 can extend any suitabledistance out from the wheel body of the wheel 400. Also, the sizing,shape, number, and relative positions of the pinion rods 450 of thewheel 400 can vary from that shown in FIG. 4.

The wheel 400 is presented as an example of an alternative embodimentconsistent with the concepts of omnidirectional pinion wheels describedherein. In other variations, a second pinion ring can be added extendingfrom the left side of the wheel 400 in FIG. 4. Additionally, anomnidirectional pinion wheel can be formed as several concentric layersof pinion rods and roller rings, with the outer-most rings being ringsof pinion rods, rings of rollers, or a ring of pinion rods on one sideof the wheel and a ring of rollers on the other side of the wheel.

Turning to other embodiments consistent with the concepts describedherein, FIG. 5A illustrates a perspective view of an exampleomnidirectional pinion wheel 500, and FIG. 5B illustrates across-sectional perspective view of the example omnidirectional pinionwheel 500 in FIG. 5A. Among other elements similar to the wheel 100, thewheel 500 includes a hub 510, a first annular rim 520, a second annularrim 530, a first annular ring of rollers including the first rollers560, and a second annular ring of rollers including the second rollers570.

Although similar to the wheel 100 in FIGS. 1 and 2, the wheel 500includes a sprocket 550 formed to extend between the first annular rim520 and the second annular rim 530 rather than pinion rods. The sprocket550 includes teeth 552 that extend out around the circumference of thesprocket 550. The teeth 552 can engage the teeth of a rack, similar tothe rack 300 in FIG. 3, so that the wheel 500 can be used to achievevertical displacement.

FIG. 6 illustrates a side view of another example omnidirectional pinionwheel 600. As shown, the wheel 600 is a type of mecanum wheel includinga pinion ring formed at one side. The wheel 600 includes a hub 620having an axis of symmetry E, a pinion ring including pinion rods 650that are secured to the hub 620 and extend between a first ring rim 652and a second ring rim 654, and an annular ring of rollers includingrollers 660 secured to the hub 620. An axle 662 of one of the rollers660 is shown by hidden lines in FIG. 6. The axle 662 extends at an angleθ as compared to the axis of symmetry E of the hub 620. In oneembodiment, the angle θ is about 45°, although other angles are withinthe scope of the embodiments.

As with the wheels 400 and 500, the wheel 600 is presented as an exampleof an alternative embodiment consistent with the concepts ofomnidirectional pinion wheels described herein. In other variations, asecond pinion ring can be added extending from the left side of thewheel 600 in FIG. 6. Additionally, an omnidirectional pinion wheel canbe formed as several concentric layers of pinion rods and roller rings,with the outer-most rings being rings of pinion rods, rings of rollers,or a ring of pinion rods on one side of the wheel and a ring of rollerson the other side of the wheel.

FIG. 7A illustrates an example vehicle 700 including omnidirectionalpinion wheels according to various embodiments, and FIG. 7B illustratesa plan view of a bottom of the vehicle 700 in FIG. 7A. While the vehicle700 is described as one example of a vehicle in which omnidirectionalpinion wheels can be used to achieve displacement in three directions,even in small or crowded spaces, it should be appreciated that theconcepts of omnidirectional pinion wheels described herein can beapplied to other types of vehicles.

The vehicle 700 includes a vehicle platform 710, an extension arm 720, aroller platform 730, wheels 740A-740D, and a retractable lateraldisplacement roller 750. Among other elements, the vehicle 700 can alsoinclude one or more batteries, drive systems, control systems,communications systems, sensors, etc. An example drive system caninclude motors, engines, gearboxes, transmissions, etc. The wheels740A-D can be mechanically coupled to the drive system to maneuver andposition the vehicle 700. An example control system can includeprocessing and/or computing systems including memory, etc. As describedin further detail below, the control system can use feedback from thesensors, such as cameras, radar systems, infrared sensors, etc., tomaneuver and position the vehicle 700 through control of the drivesystem.

In one example mode of operation, the vehicle 700 can be relied upon topick, place, and transport items from place to place in a warehouse orfulfillment center. In that context, the extension arm 720 can beembodied as a configurable robotic arm capable of moving in variousdirections within a volume of space. The extension arm 720 can be usedto pick or pull items, boxes, pallets, etc., from an adjacent shelf orrack onto the roller platform 730, for transport of the items.Similarly, the extension arm 720 can be used place items, boxes,pallets, etc., from the roller platform 730 onto an adjacent shelf orrack. Thus, the extension arm 720 and the roller platform 730 are oneexample of a transfer mechanism of the vehicle 700.

It is again noted that, because space in materials handling and otherfacilities is often limited, many facilities make use of multiplefloors, layers, levels, or platforms in rack or shelving structures.Without the use of ramps, elevators, etc., it may not be possible forvehicles in such a facility to reach or traverse across multiple floorsor levels. In that context, the wheels 740A-740D of the vehicle 700 areomnidirectional pinion wheels consistent with one or more of theembodiments described herein. Thus, in addition to being able to moveforward, backwards, and to the sides, the vehicle 700 can climbvertically between multiple floors, layers, or levels by engaging with arack or track including a rack gear. In other embodiments, the wheels740A-740D of the vehicle 700 can be omnidirectional or mecanum wheels.In that case, the vehicle 700 can climb vertically between multiplefloors, layers, or levels by engaging with a rack or track including arack gear formed to engage with the omnidirectional or mecanum wheels.

The vehicle 700 can move forward and backwards in the longitudinaldirection in response to rotation of the wheels 740A-740D clockwise orcounter-clockwise by the drive system. The vehicle 700 can move sidewaysin the lateral direction in response to a force perpendicular to theaxis of rotation of the wheels 740A-740D, if the wheels 740A-740Dinclude annular rings of rollers similar to those in the wheel 100 inFIG. 1, for example. In that case, the retractable lateral displacementroller 750 can extend down to contact the surface upon which the vehicle700 is resting, and rotate to provide a lateral (i.e., sideways) forceon the wheels 740A-740D. In response to the lateral force, the vehicle700 will move sideways in the lateral direction by rolling on theannular rings of rollers of the wheels 740A-740D. After providing thesideways force, the retractable lateral displacement roller 750 canretract back into the vehicle platform 710 so as to avoid interferingwith forward and backward movement. Alternatively, if the annular ringsof rollers of the wheels 740A-740D are independently driven, such as bymicro-motors in the wheels 740A-740D, then the lateral displacementroller 750 can be omitted. Further, if the wheels 740A-740D are similarto the wheel 600 in FIG. 6, then the lateral displacement roller 750 canbe omitted because the vehicle 700 can be moved sideways in the lateraldirection by independently rotating the wheels 740A and 740C in onedirection (e.g., clockwise) while rotating the wheels 740B and 740D inan opposite direction (e.g., counter-clockwise), as would be understoodfor mecanum wheels.

In FIG. 7B, a cross-sectional view of racks 742A-742D is also shown. Theracks 742A-742D are shown in engagement with the wheels 740A-740D,respectively. Each of the racks 742A-742D may be similar to the rack 300shown in FIG. 3 and is positioned to engage with a respective one of thewheels 740A-740D. That is, teeth of the racks 742A-742D can engage intopinion rods of the wheels 740A-740D, for example, so that the vehicle700 can be displaced vertically (e.g., lowered or raised) betweenlevels. To position the vehicle 700 into engagement with the teeth ofthe racks 742A-742D, the control system of the vehicle 700 is configuredto drive the vehicle 700 forward into the engaged position with theracks 742A-742D. In other words, the wheels 740A-740D are engaged withthe racks 742A-742D, respectively, similar to the way that the wheel 100is engaged with the rack 300 in FIG. 3.

In other embodiments, if the wheels 740A-740D of the vehicle 700 do notinclude a pinion ring or pinion rods, the racks 742A-742D can beconfigured to engage with other mechanical features of the wheels740A-740D. For example, if the wheels 740A-740D of the vehicle 700 areomnidirectional wheels, the racks 742A-742D can be configured to engagewith them in a way similar to that described below with reference toFIGS. 12A and 12B, for example.

Although FIGS. 7A and 7B illustrate one arrangement of the wheels 740A-Don the vehicle 700, the arrangement is not intended to be limiting ofthe embodiments, and the vehicle 700 (and other vehicles) can rely uponother numbers, arrangements, and orientations of omnidirectional pinionwheels. For example, although the wheels 740A and 740B are spaced moreclosely together than the wheels 740C and 740D, the wheels 740A and 740Bcould be at the same spacing as the wheels 740C and 740D. In otherembodiments, the vehicle 700 could include only three wheels rather thanfour, with one wheel at one end and the other two wheels at the otherend. In another case, the vehicle 700 could include one or more wheelsin a first orientation and one or more wheels in a second orientationperpendicular to the first orientation. In that case, if the wheelsinclude annular roller rings, certain wheels could be used for forwardand backward displacement while others are used for sidewaysdisplacement.

Further, FIGS. 8A-8C illustrate plan views of other arrangements ofwheels according to various embodiments. In FIG. 8A, among othercomponents, the vehicle 800 includes a vehicle platform 810 and wheels820A-820D. While the wheels 820A-820D are shown in FIG. 8A asomnidirectional pinion wheels (i.e., similar to the wheel 100 in FIG.1), the wheels 820A-820D can be other types of omnidirectional pinionwheels, omnidirectional wheels, mecanum wheels, or other wheels capableof longitudinal and lateral displacement. As shown, the wheels 820A and820D are placed near the center of opposing sides of the vehicleplatform 810, and the wheels 820B and 820C are placed near the center ofother opposing sides of the vehicle platform 810. In this configuration,the wheels 820A and 820D can be driven to move the vehicle 800 forwardand backward in the longitudinal direction, and the wheels 820B and 820Ccan be driven to move the vehicle 800 sideways in the lateral direction,for example.

In FIG. 8A, a cross-sectional view of racks 822A-822C in engagement withthe wheels 820A-820C, respectively, is also shown. Each of the racks822A-822C may be similar to the rack 300 shown in FIG. 3. That is, teethof the racks 822A-822C can engage into pinion rods of the wheels820A-820C, for example, so that the vehicle 800 can be displacedvertically (e.g., lowered or raised) between levels. To position thevehicle 800 into engagement with the teeth of the racks 822A-822C, acontrol system of the vehicle 800 is configured to drive the vehicle 800forward and/or to rotate the vehicle 800, as needed, into the engagedposition with the racks 822A-822C. As another example, in FIG. 8B, thevehicle 850 includes a vehicle platform 860 and wheels 870A-870D. Invarious embodiments, the wheels 870A-870D can be omnidirectional pinionwheels according to any of the embodiments described herein,omnidirectional wheels, mecanum wheels, or other wheels capable oflongitudinal and lateral displacement. As shown, each of the wheels870A-870D is placed at a respective corner of the vehicle platform 810.In this configuration, the wheels 870A and 870C can be driven to movethe vehicle 850 forward and backward in the longitudinal direction, andthe wheels 870B and 870D can be driven to move the vehicle 850 sidewaysin the lateral direction, for example.

In FIG. 8B, a cross-sectional view of racks 872A-872C in engagement withthe wheels 870A-870C, respectively, is also shown. Each of the racks872A-872C may be similar to the rack 300 shown in FIG. 3. That is, teethof the racks 872A-872C can engage into pinion rods of the wheels870A-870C, for example, so that the vehicle 850 can be displacedvertically (e.g., lowered or raised) between levels. To position thevehicle 850 into engagement with the teeth of the racks 872A-872C, acontrol system of the vehicle 850 is configured to drive and/or rotatethe vehicle 850, as needed, into the engaged position with the racks872A-872C.

As another example, in FIG. 8C, the vehicle 880 includes a vehicleplatform 882 and wheels 890A-890D. The wheels 890A-890D are shown inFIG. 8C as being similar to the omnidirectional pinion wheel 400 in FIG.4, but can be other omnidirectional pinion wheels, omnidirectionalwheels, mecanum wheels, or other wheels capable of longitudinal andlateral displacement. In FIG. 8C, a cross-sectional view of racks892A-892D in engagement with the wheels 890A-890D, respectively, is alsoshown. Each of the racks 892A-892D may be similar to the rack 300 shownin FIG. 3. That is, teeth of the racks 892A-892D can engage into pinionrods of the wheels 890A-890D, for example, so that the vehicle 880 canbe displaced vertically (e.g., lowered or raised) between levels. Toposition the vehicle 880 into engagement with the teeth of the racks892A-892D, a control system of the vehicle 880 is configured to drivethe vehicle 880 between the racks 892A-892D and to rotate, e.g.,counterclockwise as shown in FIG. 8C, the vehicle 880 into the engagedposition with the racks 892A-892D.

FIG. 9A illustrates another example vehicle 900 includingomnidirectional wheels according to various embodiments. The vehicle 900includes the vehicle platform 910, an extension arm 920, rollerplatforms 930A and 930B, and wheels 940A-940C (with a fourth wheelomitted from view). Similar to the vehicle 700, the vehicle 900 can alsoinclude one or more batteries, drive systems, control systems,communications systems, sensors, etc.

The vehicle 900 can be relied upon to pick, place, and transport itemsfrom place to place in a warehouse or fulfillment center. In thatcontext, the extension arm 920 can be used to pick or pull items, boxes,pallets, etc., from an adjacent shelf or rack onto the roller platforms930A and 930B, for transport of the items. Similarly, the extension arm920 can be used place items, boxes, pallets, etc., from the rollerplatforms 930A and 930B onto an adjacent shelf or rack. Thus, theextension arm 920 and the roller platforms 930A and 930B are an exampleof a transfer mechanism of the vehicle 900.

FIG. 9B illustrates a vehicle 950 and a pallet tender 960 transferringitems off a rack 970 and onto the vehicle 950 according to variousembodiments. The vehicle 950 is similar to the vehicle 700 shown in FIG.7 and includes an extension arm 952 similar to the extension arm 720. Asshown, the extension arm 952 can be used to pick or pull items, boxes,pallets, etc., from the rack 970 and onto the vehicle 950.Alternatively, the items can be first moved (e.g., rolled) from the rack970 onto the pallet tender 960, and then the extension arm 952 can beused to pick the items from the pallet tender 960 and onto the vehicle950. In that case, the reach of the extension arm 952 can be effectivelyincreased.

As an example track that a vehicle consistent with the embodimentsdescribed herein can use to achieve vertical displacement, FIG. 10Aillustrates a perspective view of a track 1000 for vertical displacementof omnidirectional pinion wheels according to various embodiments. Asshown, the track 1000 is formed as a c-shaped, rectangular tube havingan opening along one side. The track 1000 includes an inner surface1002, an outer surface 1004, and a rack gear 1010 that extends along alength of a side of the inner surface 1002. The rack gear 1010 canextend along the entire length of the inner surface 1002 or only alongone or more sub-lengths of the inner surface 1002. The rack gearincludes teeth 1012 similar to the teeth 310 of the rack 300 in FIG. 3.

The track 1000 can be formed from metal, plastic, or any other suitablematerial or combination of materials, without limitation. Further, thetrack 1000, which is not drawn to any particular scale or proportions inFIG. 10A, can be formed to any suitable size, length, and/or width. Thetrack 1000 can also be formed to take any suitable cross-sectionalprofile shape other than the c-shaped profile shape shown in FIG. 10A,such as full or partial circular, square, rectangular, triangular, orother shapes. Typically, the interior size and profile of the track 1000is selected or determined to correspond with the size of theomnidirectional pinion wheel that it is designed to accommodate. Forexample, the size of the track 1000 can be just large enough so that aclearance exists between the inner surface 1002 of the track 1000 andthe omnidirectional pinion wheel that fits within the track 1000.

Once an omnidirectional pinion wheel, such as the omnidirectional pinionwheel 100 in FIG. 1, is driven or rotated into the track 1000, thepinion ring of the wheel will engage with the teeth 1012. As the wheelis further rotated, the pinion ring will continue to engage with theteeth 1012, and the wheel can climb vertically within the track 1000.The clearance between the inner surface 1002 of the track 1000 and thewheel within the track 1000 allows the wheel to rotate within the track1000, but prevents the pinion ring of the wheel from falling away fromengagement with the teeth 1012.

FIG. 10B illustrates a cross-sectional view of the track 1000 in FIG.10A, and FIG. 10C illustrates a cross-sectional view of the track 1000with the omnidirectional pinion wheel 100 inside the track 1000. In FIG.10B, it can be seen that the teeth 1012 extend a distance Da from theinner surface 1002 of the track 1000 toward the interior of the track1000 and extend a distance Db in width. When used with the wheel 100,the distance Da can be selected to permit sufficient engagement with thepinion rods 150, as shown in FIG. 10C. Thus, it should be appreciatedthat, in other embodiments, the teeth 1012 can extend a smaller orlarger distance Da than that shown in FIG. 10B based on various factors,such as the dimensions of the wheel used with the track 1000, theexpected load carrying capacity of the track 1000, and other relatedfactors.

Similarly, the placement of the teeth 1012 along the inner surface 1002of the track 1000 can vary among embodiments based on the dimensions ofthe wheel used with the track 1000 and other factors. It is also notedthat the width Db of the teeth 1012 can be selected to be slightlysmaller than the length X of the pinion rods 150 (FIG. 2), to permit aclearance between the teeth 1012 and the first rim inner surface 122 andthe second rim inner surface 132 of the wheel 100.

As shown in FIGS. 10B and 10C, the wheel 100 fits within the track 1000with a small clearance between the inner surface 1002 and the first andsecond rollers 160 and 170, to allow the wheel 100 freedom to rotatewithin the track 1000, but without enough space to allow the pinion rods150 of the wheel 100 to fall away from engagement with the teeth 1012.Further, a clearance exists between the teeth 1012 and the first riminner surface 122 and the second rim inner surface 132 of the wheel 100.

As other examples of tracks, FIG. 11A illustrates a cross-sectional viewof an example track 1100, and FIG. 11B illustrates a cross-sectionalview of an example track 1120. The track 1100 in FIG. 11A includes aninner surface 1102, an outer surface 1104, and a rack gear includingteeth 1112 that extend along a length of the inner surface 1102. Ascompared to the teeth 1012 of the track 1000 shown in FIGS. 10A-10C, theteeth 1112 of the track 1100 shown in FIG. 11A extend further from theinner surface 1102 toward the interior of the track 1100 and extendfurther in width. The track 1100 can be used with a wheel other than thewheel 100, for example, such as the wheel 400 in FIG. 4. In that case,the teeth 1112 of the track 1100 could engage with the pinion rods 450of the wheel 400.

The track 1120 in FIG. 11B includes an inner surface 1122, an outersurface 1124, and two rack gears that extend along a length of the innersurface 1122. The first rack gear includes teeth 1132 and the secondrack gear includes teeth 1134. As compared to the cross-sectionalprofiles of the tracks 1000 and 1100, the cross-sectional profile of thetrack 1120 is closer to a c-shaped square rather than a c-shapedrectangle. It should be appreciated that other variations anddifferences in profiles of tracks are within the scope of theembodiments. As compared to the teeth 1012 of the track 1000 shown inFIGS. 10A-10C, the teeth 1132 and 1134 of the track 1120 shown in FIG.11B extend a shorter distance from the inner surface 1122 toward theinterior of the track 1120. The track 1120 can be used with a wheelother than the wheel 100, for example, such as a wheel including apinion ring on both outer sides. Generally, among FIGS. 10A-10C, 11A,and 11B, it can be appreciated that various track profile sizes andshapes are within the scope of the embodiments. Further, variousarrangements and sizes of rack gears and teeth configurations are withinthe scope of the embodiments.

FIG. 12A illustrates a perspective view of an example track 1200 forvertical displacement of omnidirectional wheels, and FIG. 12Billustrates a cross-sectional view of the track 1200 shown in FIG. 12Awith an omnidirectional wheel 1250 shown inside the track 1200. Theomnidirectional wheel 1250 is similar to the omnidirectional pinionwheel 100 in FIG. 1, but omits the pinion ring including the pinion rods150 from its center.

As shown, the track 1200 is formed as a c-shaped, rectangular tubehaving an opening along one side. The track 1200 includes an innersurface 1202, an outer surface 1204, and a rack gear 1210 that extendsalong a length of a side of the inner surface 1202. The rack gear 1210can extend along the entire length of the inner surface 1202 or onlyalong one or more sub-lengths of the inner surface 1202. The rack gearincludes teeth 1212 formed to engage with omnidirectional wheels.

The track 1200 can be formed from metal, plastic, or any other suitablematerial or combination of materials, without limitation. Further, thetrack 1200, which is not drawn to any particular scale or proportions inFIG. 12A, can be formed to any suitable size, length, and/or width. Thetrack 1200 can also be formed to take any suitable cross-sectionalprofile shape other than the c-shaped profile shape shown in FIG. 12A,such as full or partial circular, square, rectangular, triangular, orother shapes. Typically, as shown in FIG. 12B, the interior size andprofile of the track 1200 is selected or determined to correspond withthe size of the omnidirectional wheel 1250 that it is designed toaccommodate. For example, the size of the track 1200 can be just largeenough so that a clearance exists between the inner surface 1202 of thetrack 1200 and the omnidirectional wheel 1250 that fits within the track1200.

The rack gear 1210 is formed or configured to engage with theomnidirectional wheel 1250. Thus, once an omnidirectional wheel, such asthe omnidirectional wheel 1250, is driven or rotated into the track1200, the omnidirectional wheel will engage with the teeth 1212. Forexample, as shown in FIG. 12B, as the omnidirectional wheel 1250 isrotated in the track 1200, the teeth 1212 engage or lodge between thespaces among the rollers of the omnidirectional wheel 1250. Thus, from afirst, surface level, for example, the omnidirectional wheel 1250 can berotated or driven in engagement with the track 1200 to raise a vehicleto a second, elevated level.

It is noted that the shape, sizing, and placement of the teeth 1212along the inner surface 1202 of the track 1200 can vary amongembodiments based on the dimensions of the wheel used with the track1200 and other factors. For example, the teeth 1212 could take on adifferent shape, size, and placement when formed to engage with amecanum wheel, e.g., to engage with and/or between individual rollers ofa mecanum wheel as shown in FIG. 6, while omitting the pinion rods 650,the first ring rim 652, and the second ring rim 654.

FIG. 13A illustrates a plan view of an example system 1300 foromnidirectional transport according to various embodiments. In thesystem 1300, the vehicle 700 in FIG. 7A is resting upon a first orsurface level 1302, which may be in a materials handling facility, forexample, or another type of facility. The system 1300 also includes arack system 1310 having a second or elevated level 1312. Although thesystem 1300 is shown as having first and second levels 1302 and 1310,the rack system 1310 could include any number of levels separated fromeach other by any suitable distances.

An opening 1314, which is similar in size to that of the vehicle 700, isformed through the second level 1312. The tracks 1000A-1000D, each ofwhich are similar to the track 1000 in FIG. 10A, extend up from thefirst level 1302 to the second level 1312. The tracks 1000A-1000D arepositioned at locations that correspond to the locations of theomnidirectional pinion wheels 740A-740D of the vehicle 700. Again,although the system 1300 is shown as having the tracks 1000A-1000Dextend between the first and second levels 1302 and 1310, the system1300 could include any number of levels with various arrangements oftracks extending between them.

According to aspects of omnidirectional transport described herein, thecontrol system is configured to direct the drive system of the vehicle700 to maneuver the vehicle 700 in longitudinal and lateral directionsover the first level 1302. Similarly, to move the vehicle verticallyonto the second level 1312 of the rack system 1310, the control systemis configured to position the vehicle 700 under the opening 1314 forengagement between the omnidirectional pinion wheels 740A-740D and thetracks 1000A-1000D. Once engaged, the control system is configured todrive the omnidirectional pinion wheels 740A-740D in engagement with thetracks 1000A-1000D to raise the vehicle 700 to the second level 1312.

Once at the second level 1312, the control system is configured tomaneuver the vehicle 700 to transfer an item 1320 onto the rollerplatform 730 of the vehicle 700 at the second level 1312. For example,the extension arm 720 can be used to pick or pull the item 1320 (andother items) onto the vehicle 700. In other embodiments, other transfermechanisms can be used to pick or pull items onto the vehicle 700 orother vehicles consistent with those described herein.

After the item 1320 is on the vehicle 700, the control system isconfigured to position the vehicle 700 for engagement between theomnidirectional pinion wheels 740A-740D and tracks 1000A-1000D at thesecond level 1312. Then, the control system is configured to drive theomnidirectional pinion wheels 740A-740D in engagement with the tracks1000A-1000D to lower the vehicle 700 to the first level 1302. Once atthe first level 1302, the extension arm 720 can be used to pick or pullthe item 1320 (and other items) off the vehicle 700.

FIG. 13B illustrates a side view of part of the example system 1300shown in FIG. 13A according to various embodiments. In FIG. 13B, the twotracks 1000A and 1000D are shown. The tracks 1000A and 1000B extendsubstantially vertically from the first level 1302 to the second level1312. In other embodiments, the tracks 1000A and 1000B (or other tracks)could extend at various angles and/or curve from one or more surfaces inthe system 1300. The opening 1314 in the second level 1312 is of lengthL larger than the length of the vehicle 700. The track 1000A includes arack gear with teeth 1012A, and the track 1000D includes a rack gearwith teeth 1012D. The extension arm 720 and roller platform 730 of thevehicle 700 are omitted from view in FIG. 13B, for simplicity.

Near the first level 1302, the tracks 1000A and 1000D curve to extend atleast a length along the first level 1302, with an opening of the tracks1000A and 1000D at one end at the first level 1302. Near the secondlevel 1312, the tracks 1000A and 1000D open, with a length of the teeth1012A and 1012D extending along the second level 1312.

In FIG. 13B, the vehicle 700 is shown with the wheels 740A and 740Dengaged with the teeth 1012A and 1012D within the tracks 1000A and1000D, respectively. Although not shown in FIG. 13B, the wheels 740B and740C are engaged within the tracks 1000B and 1000C, respectively. Due tothe engagement with the teeth 1012A and 1012D, when the wheels 740A-740Dof the vehicle 700 are driven or rotated counter-clockwise, the vehicle700 will rise or be vertically displaced upwards toward the second level1312. Likewise, when the wheels 740A-740D of the vehicle 700 are drivenor rotated clockwise, the vehicle 700 will lower or be verticallydisplaced downwards toward the first level 1302. Here, it should beappreciated that, if the teeth 1012A and 1012D were formed on the otherside of the tracks 1000A and 1000D, then the wheels 740A-740D would berotated clockwise to raise the vehicle 700 and counter-clockwise tolower the vehicle 700.

The vehicle 700 can rotate the wheels 740A-740D clockwise andcounter-clockwise using its drive system. For example, motors of thedrive system can be controlled at the direction the control system ofthe vehicle, as described above, which can include one or more computingand/or control systems. The vehicle 700 can rely upon closed loop motorcontrol and sensor feedback to synchronously actuate the motors tomaintain a level or other suitable orientation of the vehicle 700 duringvertical displacement. In some embodiments, the motors can generateenergy as the vehicle 700 displaces or maneuvers from the second level1312 to the first level 1302.

Once on either of the first level 1302 or the second level 1312, thevehicle 700 is free to move about the level in any direction, asdescribed herein. That is, it should be appreciated that, based on theconcepts of omnidirectional wheels described herein, the wheels740A-740D of the vehicle 700 can be relied upon to move the vehicleforwards, backwards, or sideways on either of the first level 1302 orthe second level 1312. Further, to move between the first level 1302 andthe second level 1312, the vehicle 700 can position and engage thetracks 1000A and 1000D at one level, and drive to the other level basedon engagement with the teeth 1012A and 1012D, according to the conceptsdescribed herein.

It is noted that other omnidirectional transport systems can use othertypes of vehicles, other types of wheels, and other types, shapes,sizes, and configurations of tracks, rails, and racks consistent withthose described herein. Further, other omnidirectional transport systemscan include multiple levels of surfaces and vertical tracks to betraversed by omnidirectional vehicles.

FIG. 14 illustrates an example process 1400 of omnidirectional vehicletransport performed using the system 1300 shown in FIGS. 13A and 13Baccording to an example embodiment described herein. In certain aspects,the process flowchart in FIG. 14 can be viewed as depicting an exampleset of steps performed by the vehicle 700 in the system 1300. Theflowchart in FIG. 14 provides merely one example of a sequence orarrangement of steps that can be employed for omnidirectional vehicletransport consistent with the concepts described herein. Although theprocess 1400 is described in connection with the vehicle 700 in thesystem 1300, other vehicles, tracks, racks, etc. consistent with thosedescribed herein can be used perform the process 1400 or similarprocesses.

At reference numeral 1402, the process 1400 includes maneuvering thevehicle 700 in any longitudinal and lateral directions, for example,over the first level 1302 using the wheels 740A-740D of the vehicle 700.For example, the control system can direct the drive system of thevehicle 700 to drive the wheels 740A-740D in any suitable manner tomaneuver the vehicle 700 as needed.

At reference numeral 1404, the process 1400 includes positioning thevehicle 700 for engagement between the wheels 740A-740D and the tracks1000A-1000D at the first level 1302. Here, the control system can directthe drive system of the vehicle 700 to drive the vehicle 700 intoposition under the opening 1314 and into engagement between the wheels740A-740D and the teeth of the tracks 1000A-1000D. The positioning caninclude driving the vehicle 700 between the tracks 1000A-1000D so thatthe wheels 740A-740D engage with the tracks 1000A-1000D. In thatconfiguration, the vehicle 700 can traverse between the first level 1302and the second level 1312. As needed, the positioning can includedriving, rotating, or a combination of driving and rotating the vehicle700 into engagement with the tracks 1000A-1000D.

At reference numeral 1406, the process 1400 includes driving the wheels740A-740D in engagement with the tracks 1000A-1000D to raise the vehicle700 to the second level 1312. Further, at reference numeral 1408, theprocess 1400 includes maneuvering the vehicle 700 at the second level1312 to transfer at least one item, such as the item 1320, onto thevehicle 700 at the second level 1312. For example, once at the secondlevel 1312, the control system is configured to maneuver the vehicle 700proximate to the item 1320, so that the extension arm 720 can pick theitem 1320.

At reference numeral 1410, the process 1400 includes transferring theitem 1320 onto the vehicle 700 at the second level 1312. For example,the extension arm 720 can be used to pick or pull the item 1320 (andother items) onto the vehicle 700. In other embodiments, other transfermechanisms can be used to pick or pull items onto the vehicle 700.

At reference numeral 1412, the process 1400 includes maneuvering andpositioning the vehicle 700, with the item 1320 on the vehicle 700, forengagement between the wheels 740A-740D and the tracks 1000A-1000D atthe second level 1312. Here, the control system can direct the drivesystem of the vehicle 700 to drive the vehicle 700 into position overthe opening 1314 and into engagement between the wheels 740A-740D andthe teeth of the tracks 1000A-1000D. The positioning can include drivingthe vehicle 700 between the tracks 1000A-1000D at the second level sothat the wheels 740A-740D engage with the tracks 1000A-1000D. As needed,the positioning can include driving, rotating, or a combination ofdriving and rotating the vehicle 700 into engagement with the tracks1000A-1000D.

At reference numeral 1414, the process 1400 includes driving the wheels740A-740D to lower the vehicle 700 to the first level 1302. At referencenumeral 1416, the process 1400 includes maneuvering the vehicle 700 inany longitudinal and lateral directions, for example, over the firstlevel 1302 using the wheels 740A-740D of the vehicle 700. For example,the control system can direct the vehicle 700 to move to a location fortransport or delivery of the item 1320. At reference numeral 1418, theprocess 1400 includes transferring the item 1320 off the vehicle 700 atthe first level 1302.

Although embodiments have been described herein in detail, thedescriptions are by way of example. The features of the embodimentsdescribed herein are representative and, in alternative embodiments,certain features and elements can be added or omitted. Additionally,modifications to aspects of the embodiments described herein can be madeby those skilled in the art without departing from the spirit and scopeof the present invention defined in the following claims, the scope ofwhich are to be accorded the broadest interpretation so as to encompassmodifications and equivalent structures.

Therefore, at least the following is claimed:
 1. A wheel, comprising: ahub comprising a center bore that extends in a first direction; a firstannular rim comprising a first rim inner surface and a first rim outersurface; a second annular rim comprising a second rim inner surface anda second rim outer surface, the first rim inner surface being spacedapart from the second rim inner surface by a distance in the firstdirection; a first plurality of spokes that extend radially away fromthe hub to the first annular rim; a second plurality of spokes thatextend radially away from the hub to the second annular rim; a pluralityof pinion rods that extend between and separate the first rim innersurface and the second rim inner surface by the distance in the firstdirection, the plurality of pinion rods being substantially evenlyspaced along the first annular rim and the second annular rim; a firstannular ring of rollers comprising a first plurality of rollers arrangedin a first ring and affixed to the first rim outer surface; and a secondannular ring of rollers comprising a second plurality of rollersarranged in a second ring and affixed to the second rim outer surface.2. The wheel according to claim 1, wherein: the first annular ring ofrollers is affixed apart in the first direction from the first rim outersurface; the second annular ring of rollers is affixed apart in thefirst direction from the second rim outer surface; at least one rollerof the first plurality of rollers is affixed to the first rim outersurface through an axle that provides a rotational axis of freedom aboutan axis of symmetry of the at least one roller; and a direction of theaxis of symmetry of the at least one roller is substantially orthogonalto the first direction of the center bore of the hub.
 3. The wheelaccording to claim 1, wherein: the first annular ring of rollers issymmetrically offset from the second annular ring of rollers; and thefirst annular ring of rollers and the second annular ring of rollersextend a greater distance radially away from the hub than the firstannular rim and the second annular rim.
 4. A wheel, comprising: a hubhaving an axis of symmetry that extends in a first direction; a firstannular rim and a second annular rim; a wheel body that extends radiallyaway from the hub to one of the first annular rim or the second annularrim; an annular ring of rollers comprising a plurality of rollersarranged in a ring around and affixed to an outer surface of one of thefirst annular rim or the second annular rim, at least one roller amongthe plurality of rollers having a rotational axis of freedom about anaxle secured to the outer surface of the one of the first annular rim orthe second annular rim; and a plurality of pinion rods that extend inthe first direction between and separate an inner surface of the firstannular rim and an inner surface of the second annular rim.
 5. The wheelaccording to claim 4, wherein the wheel body comprises a plurality ofspokes that extend radially away from the hub to the annular rim.
 6. Thewheel according to claim 4, wherein the plurality of pinion rods form apinion ring that extends between and separates the inner surface of thefirst annular rim and the inner surface of the second annular rim. 7.The wheel according to claim 4, wherein a direction of the rotationalaxis of freedom of the at least one roller is substantially orthogonalto the first direction in which the plurality of pinion rods extend. 8.The wheel according to claim 7, wherein: the wheel can be displaced on asurface in a direction substantially orthogonal to the first directionin response to rotation of the wheel about the axis of symmetry of thehub; and using the rotational axis of freedom of the at least oneroller, the wheel can be displaced on the surface in the first directionin response to a force on the wheel in the first direction.
 9. The wheelaccording to claim 4, further comprising: a second wheel body thatextends radially away from the hub to another one of the first annularrim or the second annular rim; and a second annular ring of rollerscomprising a second plurality of rollers arranged in a ring around andaffixed to an outer surface of another one of the first annular rim orthe second annular rim.
 10. The wheel according to claim 9, wherein theannular ring of rollers is symmetrically offset from the second annularring of rollers.
 11. A system, comprising: a vehicle comprising at leastone wheel, wherein the at least one wheel comprises: a hub comprising anaxis of symmetry that extends in a first direction; a first annular rimand a second annular rim; a wheel body that extends radially away fromthe hub to one of the first annular rim or the second annular rim; anannular ring of rollers comprising a plurality of rollers arranged in aring around and affixed to an outer surface of one of the first annularrim or the second annular rim, at least one roller among the pluralityof rollers having a rotational axis of freedom about an axle secured tothe outer surface of the one of the first annular rim or the secondannular rim; and a plurality of pinion rods that extend between andseparate an inner surface of the first annular rim and an inner surfaceof the second annular rim; and at least one track comprising a rack gearformed to engage with the at least one wheel of the vehicle to raise orlower the vehicle.
 12. The system according to claim 11, wherein the atleast one wheel fits within the at least one track with a clearancebetween the at least one track and the annular ring of rollers of the atleast one wheel.
 13. The system according to claim 11, wherein: the hubhas an axis of symmetry that extends in a first direction; and theplurality of pinion rods extend between the first annular rim and thesecond annular rim in the first direction.
 14. The system according toclaim 13, wherein the plurality of pinion rods form a pinion ring thatextends between and separates the inner surface of the first annular rimand the inner surface of the second annular rim.
 15. The systemaccording to claim 13, wherein: at least a length of the at least onetrack extends vertically; and the plurality of pinion rods of the atleast one wheel can engage with the rack gear of the at least one trackfor vertical displacement of the vehicle.
 16. The system according toclaim 11, wherein: the vehicle comprises a plurality of wheels; the atleast one track comprises a plurality of tracks, at least one of theplurality of tracks including the rack gear; individual ones of theplurality of wheels fit within respective ones of the plurality oftracks with a clearance; and the at least one wheel can engage with therack gear for vertical displacement of the vehicle.
 17. The systemaccording to claim 11, wherein the at least one wheel further comprises:a second wheel body that extends radially away from the hub to anotherone of the first annular rim or the second annular rim; and a secondannular ring of rollers comprising a second plurality of rollersarranged in a ring around and affixed to an outer surface of another oneof the first annular rim or the second annular rim.
 18. The systemaccording to claim 17, wherein the annular ring of rollers issymmetrically offset from the second annular ring of rollers.
 19. Thesystem according to claim 11, wherein the annular ring of rollers isaffixed apart in the first direction from the outer surface of the oneof the first annular rim or the second annular rim.
 20. The systemaccording to claim 19, wherein the at least one wheel further comprisesa second annular ring of rollers affixed apart in the first directionfrom an outer surface of another one of the first annular rim or thesecond annular rim.